U-boot config options used in fec_mxc.c
  
  CONFIG_FEC_MXC
  	Selects fec_mxc.c to be compiled into u-boot.
  
  CONFIG_MII
  	Must be defined if CONFIG_FEC_MXC is defined.
  
  CONFIG_FEC_XCV_TYPE
  	Defaults to MII100 for 100 Base-tx.
  	RGMII selects 1000 Base-tx reduced pin count interface.
  	RMII selects 100 Base-tx reduced pin count interface.
  
  CONFIG_FEC_MXC_SWAP_PACKET
  	Forced on iff MX28.
  	Swaps the bytes order of all words(4 byte units) in the packet.
  	This should not be specified by a board file. It is cpu specific.
  
  CONFIG_PHYLIB
  	fec_mxc supports PHYLIB and should be used for new boards.
  
  CONFIG_FEC_MXC_NO_ANEG
  	Relevant only if PHYLIB not used. Skips auto-negotiation restart.
  
  CONFIG_FEC_MXC_PHYADDR
  	Optional, selects the exact phy address that should be connected
  	and function fecmxc_initialize will try to initialize it.